top-level: drop x86_64-darwin deprecation warning

It's annoying to see this poping up all over the place in my CI.

Author: Mic92

pkgs/top-level/default.nix

@@ -18,25 +18,6 @@
   or dot-files.
 */
 
-let
-  # We hoist this above the closure so that the same thunk is shared
-  # between multiple imports of Nixpkgs. This ensures that commands
-  # like `nix eval nixpkgs#legacyPackages.x86_64-darwin.pkgsStatic.hello`
-  # print only one warning, which would otherwise be spammy in common
-  # scenarios that instantiate many copies of Nixpkgs.
-  #
-  # Unfortunately, flakes’ handling of transitive dependencies mean
-  # that it’s still likely users will see multiple warnings, but
-  # there’s nothing we can do about that within the constraints of the
-  # Nix language.
-  x86_64DarwinDeprecationWarning =
-    pristineLib.warn
-      "Nixpkgs 26.05 will be the last release to support x86_64-darwin; see https://nixos.org/manual/nixpkgs/unstable/release-notes#x86_64-darwin-26.05"
-      (x: x);
-
-  pristineLib = import ../../lib;
-in
-
 {
   # The system packages will be built on. See the manual for the
   # subtle division of labor between these two `*System`s and the three
@@ -74,6 +55,8 @@ let # Rename the function arguments
 
 in
 let
+  pristineLib = import ../../lib;
+
   lib =
     if __allowFileset then
       pristineLib
@@ -99,17 +82,8 @@ let
     (throwIfNot (lib.isList overlays) "The overlays argument to nixpkgs must be a list.")
       (throwIfNot (lib.all lib.isFunction overlays) "All overlays passed to nixpkgs must be functions.")
       (throwIfNot (lib.isList crossOverlays) "The crossOverlays argument to nixpkgs must be a list.")
-      (throwIfNot (lib.all lib.isFunction crossOverlays) "All crossOverlays passed to nixpkgs must be functions.")
       (
-        if
-          (
-            ((localSystem.isDarwin && localSystem.isx86) || (crossSystem.isDarwin && crossSystem.isx86))
-            && config.allowDeprecatedx86_64Darwin == false
-          )
-        then
-          x86_64DarwinDeprecationWarning
-        else
-          x: x
+        throwIfNot (lib.all lib.isFunction crossOverlays) "All crossOverlays passed to nixpkgs must be functions."
       );
 
   localSystem = lib.systems.elaborate args.localSystem;